C4. Antifungal agents Flashcards

1
Q

What is the MOA of Amphotericin B?

A

Binds ergosterol and forms pores in fungal cell membrane.

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2
Q

What are the indications for caspofungin?

A
  1. Invasive aspergillosis
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3
Q

What are the side effects of Anidulafungin?

A
  1. May cause HA release on infusion → flushing.
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4
Q

What are the side effects of micafungin?

A
  1. Increases risk of hepatic cancer
  2. Suppresses bone marrow
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5
Q

What is the MOA of Flucytosine?

A

converted into 5-fluorouracilhalts DNA/RNA synthesis.

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6
Q

What are the SE of Flucytosine?

A
  1. Bone marrow suppression
  2. Hepatotoxicity
  3. May cause toxic enterocolitis at high doses
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7
Q

What is the MOA of Nystatin?

A

Same as amphotericin, binds ergosterol and forms pores in fungal cell membrane.

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8
Q

What is the MOA of Azoles?

A

Azoles inhibit ergosterol synthesis from lanosterol via fungal CYP450 (14-alpha demethylase).

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9
Q

List the First Generation Triazoles?

A
  1. Fluconazole
  2. Itraconazole
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10
Q

What are the indications for Itraconazole?

A
  1. Good for dimorphic fungi (Histo, Blasto, Coccidio, Sporothrix) and for onychomycosis and dermatophytosis (tinea) … remember T drugs for tinea (Keto-/Clotrim-/Itraconazole, Terbinafine)
  2. Also effective in Aspergillus infections.
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11
Q

What are the indications for Fluconazole?

A
  1. Mucocutaneous Candidiasis (1x oral dose for vaginal candidiasis, IV for esophagitis)
  2. Cryptococcal meningitis (treatment and prophylaxis)
  3. Sepsis in ICU
  4. Skin and nails infections
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12
Q

List the second generation of triazoles.

A
  1. Ketoconazole
  2. Clotrimazole
  3. Imidazoles
  4. Posaconazole
  5. Voriconazole
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13
Q

What are the indications for Ketoconazole?

A
  1. For topical use in dermatophytos
  2. Can help in Cushing’s to ↓ cortisol production…due to the androgen/estrogen synthesis inhibition.
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14
Q

What are the indications for Clotrimazole?

A

Good for dermatophytosis and vaginal candidiasis topically.

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15
Q

What is important to remember about the imidazoles?

A

That they are not used systemically.

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16
Q

What are the indications of Posaconazole?

A

Posaconazole is a triazole antifungal drug that is used to treat invasive infections by Candida species and Aspergillus species in severely immunocompromised patients.

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17
Q

What are the indications of Voriconazole?

A
  1. Invasive Aspergillosis
  2. Candida esophagitis (in AIDS patients)
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18
Q

What spectrum does Amphotericin B cover?

A
  1. Broadest anti-fungal used for severe systemic fungal infections:
    • Histo
    • Coccidio
    • Blasto
    • Crypto meningitis (with flucytosine)
    • Systemic candidiasis
    • Works for all fungi except dermatophytes
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19
Q

What are the side effects of Amphotericin B?

A

Mostly by non-specific cholesterol binding

  1. Immediate: infusion-related; fever, chill, spasm, vomiting, headache + hypotension
  2. Slower: renal damage (tubular injury, T1RTA → hypokalemia, azotemia, Mg wasting); anemia (via ↓ EPO) can give IV saline to minimize ↓ GFR and renal damage
  3. Thrombophlebitis at injection site
  4. Seizures and neuro damage if intrathecal
20
Q

List the other anti-fungals:

A
  1. Echinocandins
  2. Terbinafine
  3. Griseofulvin
21
Q

What is the MOA of Echinocandins?

A

Echinocandins inhibit synthesis of polysaccharide glucan in synthesis of cell wall (not the membrane!)

22
Q

What are the indications of Terbinafine?

A
  1. Used topically for dermatophytosis (first-line for tinea capitis in kids)
  2. Used orally for onychomycosis (also deposits in keratin tissues)
23
Q

What are the indications of Griseofulvin?

A

It accumulates in keratin-producing tissues given orally for dermatophytosis; long-term for onychomycosis.

24
Q

What spectrum does nystatin cover?

A

Most Candida species

25
Q

What are the side effects of Azoles?

A
  1. Interactions - via CYP450 inhibition
26
Q

List the antifungal treatment options.

A
  1. Antibiotics
  2. Antimetabolites
  3. Azoles
  4. Allylamines
  5. Echinocandins
27
Q

List the Echinocandins.

A
  1. Caspofungin
  2. Anidulafungin
  3. Micafungin
28
Q

List the Allylamines.

A
  1. Terbinafine
  2. Naftitine
29
Q

List the azoles.

A
  1. Imidazoles: Ketoconazole, Clotrimazole, Oxiconazole, Miconazole.
  2. Triazoles: Fluconazole, Itraconazole, Voriconazole, Posaconazole.
30
Q

List the antimetabolites.

A
  1. Flucytosine
31
Q

List the antibiotics.

A
  1. Polyene: Amphotericin B, Nystatin
  2. Heterocyclic benzofuran: Griseofulvin
32
Q

What are the indications of Flucytosine therapy?

A

Often given in combo with amphotericin for Cryptococcal meningitis combination causes ↑ 5-FC entry, ↓ toxicity + therapy duration, and ↓ resistance.

33
Q

Does Itraconazole penetrate the CNS?

A

It has poor CNS entry.

34
Q

Can Fluconazole penetrate the CNS?

A

Yes, it penetrates CNS well.

35
Q

What is the route of administration of Ketoconazole?

A

ONLY used locally, is not given systemically, because has worse CYP450 and androgen/estrogen synthesis inhibition (→ gynecomastia, oligospermia, impotence).

36
Q

List the Imidazoles.

A
  1. Clotrimazole
  2. Ketoconazole
37
Q

What interaction can Voriconazoles have?

A

Particularly strong CYP450 inhibitor.

38
Q

What are the side effects of Voriconazoles?

A

It can cause visual disturbances - light flashes, ↓ color vision.

39
Q

What is the route of administration of Echinocandins?

A

It is given IV

40
Q

What are the indications of Echinocandins?

A

Highly effective for systemic Candida (mucocutaneous, esophageal and candidemia).

41
Q

How are the pharmacokinetic parameters of Amphotericin B?

A
  1. IV admin only
  2. Liposomal form exists → ↓ cholesterol binding → ↓ toxicity.
  3. Intrathecal admin for CNS fungal infections.
  4. Often combined with flucytosine for cryptococcal infection.
42
Q

What are the side effects of Echinocandins?

A
  1. well tolerated
  2. minor GI effects + flushing
43
Q

What is the MOA of Terbinafine?

A

Terbinafine interferes with ergosterol synthesis via squalene epoxidase inhibition → accumulation of toxic squalene → fungicidal effect.

44
Q

What are the side effects of Terbinafine?

A
  1. GI effects
  2. Hepatotoxicity
45
Q

What is the MOA of Giseofulvin?

A

Giseofulvin binds to fungal microtubules → halts mitosis, acting as a fungistatic.

46
Q

What is the route of administration of Nystatin?

A

Available topically or as a rinse (oral candidiasis); not given systemically.

47
Q

What are the side effects of Griseofulvin?

A
  1. GI symptoms
  2. Headache
  3. Rash
  4. Hepatotoxicity
  5. Granulocytopenia
  6. Induces CYP450 enzymes